Patent Literature 1 is one of background arts in the technical field. An object of Patent Literature 1 is to accurately detect plural types of objects. Therefore, disclosed is a stereo camera that divides an image into small regions, makes the small regions correspond with each other between plural images on the basis of the similarity of the brightness value to generate distance image data obtained by measuring distances, detects an object as one measurement target by grouping the small regions with the measured distances closer to each other, and measures the distance up to the object as the average value of the distances in the group.
Further, an object of Patent Literature 2 is to measure a distance up to an object by accurately detecting the object to be measured, as similar to Patent Literature 1. Thus, in addition to the grouping using the distance image data, small regions in which the brightness values of adjacent pixels are closer to each other in one image are grouped. Accordingly, disclosed is a stereo camera that can reliably detect an object as one measurement target to measure the distance up to the object as the average value of the distances in the group on the assumption that adjacent brightness values are not largely changed in the same object even in the case where the small regions cannot be grouped due to irregularities of the measured distances caused by the influence of the sizes of the small regions and division positions in spite of the same object.